MPO and ischemia: Compared with the control group, xanthione peroxidase (XO) and myeloperoxidase (MPO) activity in the vehicle-treated group significantly increased, by 6.154- and 3.326-fold, respectively, 24 h after ischemia/reperfusion, and by 4.265- and 2.986-fold, respectively, 72 h after ischemia/reperfusion.